I own LS3/5As which are roughly the same as your speakers, but somewhat higher sensitivity than the 83dB of the LS3/5As. You don't need a lot of power to make these speakers perform as they were designed. Also, they respond well to voltage changes so they are very good with smallish (18-25W) tube amps.
But, as Bob Reynolds suggested, you are asking too much from your amp. It really is best with you sitting 6-8 feet away and the speaker separated by the same amount, pulled at least 1M away from side and back walls. If you do this, you will hear the true glory of these speakers.
The Quad 12L will give you more bass and a more extended treble at the expense of sound staging. It will work better in a bigger room, and so on....up the line
But, as Bob Reynolds suggested, you are asking too much from your amp. It really is best with you sitting 6-8 feet away and the speaker separated by the same amount, pulled at least 1M away from side and back walls. If you do this, you will hear the true glory of these speakers.
The Quad 12L will give you more bass and a more extended treble at the expense of sound staging. It will work better in a bigger room, and so on....up the line